A LED metal substrate includes two parts of a LED chip and a metal core substrate. The LED chip is attached onto the metal core substrate and then the LED chip is subject to bonding, so that the LED chip is electrically connected to a circuit on the metal core substrate. Such LED metal substrate may be generally referred as a chip on board (COB).
Because such LED metal substrate may be mainly mounted in lighting, the LED metal substrate may be required to meet requirements of light efficiency and a safety requirement of lighting. Regarding the safety of lighting, breakdown voltage is one of indexes of safety and mainly used to indicate a performance for preventing electric breakdown. The breakdown voltage and the performance of preventing electric breakdown increase gradually as the level of breakdown voltage increases from level 0, to level I, and then to level II.
It is found that there is defect in the prior art that, it is difficult to increase the breakdown voltage of the prior LED metal substrate to high level due to the limitation on the dimension of the LED metal substrate.